Squeak Etoys is a "media authoring tool"-- software that you can download to your computer
and then use to create your own media. You can write out your project and share it with others.
Etoys runs on any Mac or Windows machine, as well as on the OLPC XO machine.
It is free.
Find out about Etoys.

Text of this guide (for searching): Menu Tools: Simple and Detailed Watchers Found in the Viewer
This simple watcher shows the X position of the oval on the page.
Move the oval left or right and the location number will change. Open the blue oval's Viewer and click on the Scriptor's white menu to the left of the tiles.
This detailed watcher shows the Y position. Move this ellipse. Drag the yellow ellipse out of the book.
Its watchers will tell where it is in
the world too. Even when the Viewer is closed, the watchers show information.
Make changes with the watchers too. Click the tiny green arrows, or highlight the number, type in a new one and press Enter.